This invention relates to an elevator control apparatus for controlling the service of an elevator, and more particularly to an elevator control apparatus which can readily add or modify operating steps in the service of the elevator when there is a change in the control requirement from one mode of control to another.
A prior-art apparatus of this type is described in Japanese Patent Application Laid-open No. 56-99504, and the circuit block diagram thereof is shown in FIG. 6.
Referring to the figure, the prior-art control apparatus for an elevator comprises a central processing unit (hereinbelow, termed `CPU`) 1 for determining operating steps necessary for an elevator service on the basis of state and control signals supplied from operating devices 5 and in accordance with predetermined sequences stored in a memory unit 2. The memory unit 2 includes a standard-mode ROM 21 for storing sequences to be applied in standard operations and a modified-mode ROM 23 for storing sequences to be applied in special operations. A contact memory unit 3 is further provided to store data of relay contact states in the final operation of the elevator controlled by the CPU 1 while a coil memory unit 4 is provided to store data of the relay coil states of the operating steps determined by the CPU 1 on the basis of the data stored in the contact memory unit 3 and the state and control signals supplied from the operating devices 5. An input data memory unit 6 temporarily holds the state and control signals output from the devices 5 while an output data memory unit 7 temporarily holds, under the control of the CPU 1, data of the relay coil states stored in the coil memory unit 4. A main bus 8 connects the aforementioned units so as to transfer the data and signals therebetween.
Next, the operation of the prior-art apparatus based on the above arrangement will be described with reference to FIGS. 7 to 10. FIG. 7 shows an operational flow chart relating to the operations of various elements shown in FIG. 6 in which arrows in solid lines indicate the flows of data or signals, while the arrows in broken lines indicate the flows of the operations. To start (START) the operations, the CPU 1 is first initialized (INITL) to send clear signals to the contact memory unit 3 (RELAY CONTACT STATES OPERATION) and coil memory unit 4 (RELAY COIL STATES OPERATION) to clear the data of relay contact states used in a preceding service so as to eliminate the influence thereof on the new service. When state signals and control signals of the elevator devices 5 are input (INPUT OPERATION) and temporarily stored (DATA INPUT OPERATION) the input data memory unit 6. The operating steps necessary for the elevator service are simulated by the CPU 1 on the basis of these state and control signals and according to the standard-mode (STANDARD-MODE DECISION OPERATION) or the modified-mode (MODIFIED-MODE DECISION OPERATION). The data of relay coil states are then stored in the coil memory unit 4 (RELAY COIL STATES OPERATION).
In a case where the CPU 1 has decided from the state signals and control signals that the operations of the elevator are standard, the operating steps are determined by only the standard sequences stored in the standard-mode ROM 21. If, on the other hand, the CPU 1 has decided that special operations of the elevator are in progress, the special sequences stored in the modified-mode ROM 23 are included in the determination of the operating steps.
On the basis of the operating steps stored in the coil memory unit 4, the CPU 1 calculates operation command signals and display signals and stores them in the output data memory unit 7 as output data and delivers them to the operating devices 5 (OUTPUT OPERATION) so as to cause the elevator to perform predetermined operations. In addition, the CPU 1 transmits (TRANSMITTING OPERATION) the relay coil states currently stored in the coil memory unit 4 to the contact memory unit 3 as the relay contact states of the final operation of the elevator and stores them therein (RELAY CONTACT STATES OPERATION).
The elevator control apparatus therefore controls the service of the elevator under the condition that the special sequences stored in the modified-mode ROM 23 remains unchanged during the current and subsequent service operations.
Next, the relation between the standard and special sequences will be described in detail with reference to FIGS. 8(a) and 8(b). As illustrated in FIG. 8(a), the standard sequences A successively simulates processing units formed of relay circuits A10-A40 having a plurality of relay contact circuits A11-A41 and relay coils A12-A42. Each relay contact circuit includes a pair of contacts (for example, contacts A12A and A12B for circuit A11) so that when the corresponding relay coil (A12 in the example) is energized, one contact is closed and the other opened, depending on the state of the relay coil. For illustration purposes, the contact A12B is closed in the relay contact circuit A11 while the contact A42A is opened in the relay contact circuit A41. It is also noted that, in FIG. 7, only relay coil A22 and the contacts A22A and A22B of relay circuit A20 are represented for simplicity. In FIG. 8(b), which illustrates the special sequences B, only one processing unit formed of relay circuit B10 is represented to include a relay contact circuit B11 and a relay coil B12. Other processing units of similar construction and corresponding to other processing units A20-A40 of the standard sequences A are omitted for simplicity. Since the relay contact circuits provide the function of detecting a "hall call" to stop the elevator cage at the floor corresponding to the hall call while the cage is running, they are hereinafter referred to as the stoppage determining circuits of the relay coils. One such stoppage determining circuit in the standard sequence A, which operates between a first floor and a fifth floor, is described in detail with reference to FIG. 9.
Referring to the figure, reference symbols (+) and (-) designate a DC power source and A22 a hall call stoppage determining relay coil. The stoppage determining circuit A21 comprises cage position relay contacts 1F-4F which are closed when the cage approaches the first floor-fourth floor, respectively. Similarly, cage position relay contacts 2G-5G are relay contacts for the second floor-fifth floor. Reference numerals 1U-4U designate up call relay contacts which are closed when respective up hall calls on the first floor-fourth floor have been registered, 2D-5D designate down call relay contacts which are closed when respective down hall calls on the second floor-fifth floor have been registered, and 6A and 6B designate control relay contacts which are closed during normal operation of the elevator cage. "Up" service relay contact 7B is closed during an upward operation of the cage and, similarly, a down service relay contact 8B is closed during a downward operation of the cage. "Up" travel relay contact 9A is closed during the travel of the cage in an upward direction and, similarly, a down travel relay contact 10A is closed during the travel of the cage in a downward direction. The hall call stoppage determining relay coil A.sub.22 generates a command signal for stopping the elevator cage in response to the registration of a hall call when the relay coil A22 is energized.
With the above circuit arrangement, when an up hall call is made at, for instance, the third floor and the cage, in normal (standard) operation, traveling in the upward direction approaching the third floor, the hall call stoppage determining relay coil A.sub.22 is energized by a circuit extending along (+)-(3F)-(3U)-(6A)-(9A)-(A.sub.22)-(-), and the cage commences deceleration for stopping at the third floor in accordance with known car stopping and leveling circuitry (not shown). When the cage is traveling in the upward direction and no up hall call is made, and, therefore, upward operation is not needed, the up service relay contact 7B is closed, and the cage is stopped by a circuit extending along (+)-(7B)-(9A)-(A.sub.22)-(-).
In most elevators, this circuit arrangement is used for the hall call stoppage determination. However, in a manually operated elevator which is provided with passage buttons, a circuit arragenment shown in FIG. 10 containing partial modification becomes necessary.
The circuit in FIG. 10 is also a hall call stoppage determining circuit for an elevator to be used in special operation. In the figure, symbol B.sub.12 denotes a hall call stoppage determining relay coil for generating a command signal for stopping the elevator cage in response to the registration of a hall call when the relay coil B12 is energized, and symbols 12A and 12B denote passage (non-stop) relay contacts which are opened when a passage button has been depressed in the cage. The remaining elements are the same as in FIG. 9. In this case, when an up hall call is made at the third floor, and the cage, in normal operation, is traveling in the upward direction approaching the third floor, if the passage relay contact 12A is pressed open, the hall call stoppage determining relay coil B12 will not be energized and the cage passes the third floor without stopping.
Thus, when the elevator is required to operate in a manner different from the standard operation, modifications to the elevator control circuit are necessary. These modifications, such as the addition of the "non-stop" mode, may be effected by the addition of further switches and relays to the standard control circuit.
In the prior-art example described above, the standard and special sequences are all stored in the read only memories 21 and 23 of the memory unit 2 shown in FIG. 6.
This has led to the problem that the special sequence steps are fixed, so the elevator can no longer be operated under a special mode requiring variable special sequence steps. Furthermore, the storage of the special sequences in the read only memory unit brings about the disadvantage that the memory unit itself needs to be separately prepared for replacement or that a ROM wrtier dedicated to writing data is required.